Clock



FIG. 1 is a front elevational view of a clock showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a side elevational view showing one side thereof;

FIG. 4 is a side elevational view showing an opposite side thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a top plan view thereof.

The surface indicia shown in broken lines in FIG. 1 are for environmental purposes only and form no part of the claimed design. 

The ornamental design for a clock, as shown and described. 